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scrapework.go
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scrapework.go
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package promscrape
import (
"bytes"
"flag"
"fmt"
"io"
"math"
"math/bits"
"strings"
"sync"
"time"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/auth"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/bloomfilter"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/cgroup"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/decimal"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/encoding"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/fasttime"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/flagutil"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/leveledbytebufferpool"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/prompbmarshal"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/promrelabel"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/promutils"
parser "github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus/stream"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/proxy"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/timerpool"
"github.com/VictoriaMetrics/metrics"
"github.com/cespare/xxhash/v2"
)
var (
suppressScrapeErrors = flag.Bool("promscrape.suppressScrapeErrors", false, "Whether to suppress scrape errors logging. "+
"The last error for each target is always available at '/targets' page even if scrape errors logging is suppressed. "+
"See also -promscrape.suppressScrapeErrorsDelay")
suppressScrapeErrorsDelay = flag.Duration("promscrape.suppressScrapeErrorsDelay", 0, "The delay for suppressing repeated scrape errors logging per each scrape targets. "+
"This may be used for reducing the number of log lines related to scrape errors. See also -promscrape.suppressScrapeErrors")
minResponseSizeForStreamParse = flagutil.NewBytes("promscrape.minResponseSizeForStreamParse", 1e6, "The minimum target response size for automatic switching to stream parsing mode, which can reduce memory usage. See https://docs.victoriametrics.com/vmagent.html#stream-parsing-mode")
)
// ScrapeWork represents a unit of work for scraping Prometheus metrics.
//
// It must be immutable during its lifetime, since it is read from concurrently running goroutines.
type ScrapeWork struct {
// Full URL (including query args) for the scrape.
ScrapeURL string
// Interval for scraping the ScrapeURL.
ScrapeInterval time.Duration
// Timeout for scraping the ScrapeURL.
ScrapeTimeout time.Duration
// How to deal with conflicting labels.
// See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#scrape_config
HonorLabels bool
// How to deal with scraped timestamps.
// See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#scrape_config
HonorTimestamps bool
// Whether to deny redirects during requests to scrape config.
DenyRedirects bool
// OriginalLabels contains original labels before relabeling.
//
// These labels are needed for relabeling troubleshooting at /targets page.
//
// OriginalLabels are sorted by name.
OriginalLabels *promutils.Labels
// Labels to add to the scraped metrics.
//
// The list contains at least the following labels according to https://www.robustperception.io/life-of-a-label/
//
// * job
// * instance
// * user-defined labels set via `relabel_configs` section in `scrape_config`
//
// See also https://prometheus.io/docs/concepts/jobs_instances/
//
// Labels are sorted by name.
Labels *promutils.Labels
// ExternalLabels contains labels from global->external_labels section of -promscrape.config
//
// These labels are added to scraped metrics after the relabeling.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3137
//
// ExternalLabels are sorted by name.
ExternalLabels *promutils.Labels
// ProxyURL HTTP proxy url
ProxyURL *proxy.URL
// Auth config for ProxyUR:
ProxyAuthConfig *promauth.Config
// Auth config
AuthConfig *promauth.Config
// Optional `relabel_configs`.
RelabelConfigs *promrelabel.ParsedConfigs
// Optional `metric_relabel_configs`.
MetricRelabelConfigs *promrelabel.ParsedConfigs
// The maximum number of metrics to scrape after relabeling.
SampleLimit int
// Whether to disable response compression when querying ScrapeURL.
DisableCompression bool
// Whether to disable HTTP keep-alive when querying ScrapeURL.
DisableKeepAlive bool
// Whether to parse target responses in a streaming manner.
StreamParse bool
// The interval for aligning the first scrape.
ScrapeAlignInterval time.Duration
// The offset for the first scrape.
ScrapeOffset time.Duration
// Optional limit on the number of unique series the scrape target can expose.
SeriesLimit int
// Whether to process stale markers for the given target.
// See https://docs.victoriametrics.com/vmagent.html#prometheus-staleness-markers
NoStaleMarkers bool
// The Tenant Info
AuthToken *auth.Token
// The original 'job_name'
jobNameOriginal string
}
func (sw *ScrapeWork) canSwitchToStreamParseMode() bool {
// Deny switching to stream parse mode if `sample_limit` or `series_limit` options are set,
// since these limits cannot be applied in stream parsing mode.
return sw.SampleLimit <= 0 && sw.SeriesLimit <= 0
}
// key returns unique identifier for the given sw.
//
// It can be used for comparing for equality for two ScrapeWork objects.
func (sw *ScrapeWork) key() string {
// Do not take into account OriginalLabels, since they can be changed with relabeling.
// Do not take into account RelabelConfigs, since it is already applied to Labels.
// Take into account JobNameOriginal in order to capture the case when the original job_name is changed via relabeling.
key := fmt.Sprintf("JobNameOriginal=%s, ScrapeURL=%s, ScrapeInterval=%s, ScrapeTimeout=%s, HonorLabels=%v, HonorTimestamps=%v, DenyRedirects=%v, Labels=%s, "+
"ExternalLabels=%s, "+
"ProxyURL=%s, ProxyAuthConfig=%s, AuthConfig=%s, MetricRelabelConfigs=%q, "+
"SampleLimit=%d, DisableCompression=%v, DisableKeepAlive=%v, StreamParse=%v, "+
"ScrapeAlignInterval=%s, ScrapeOffset=%s, SeriesLimit=%d, NoStaleMarkers=%v",
sw.jobNameOriginal, sw.ScrapeURL, sw.ScrapeInterval, sw.ScrapeTimeout, sw.HonorLabels, sw.HonorTimestamps, sw.DenyRedirects, sw.Labels.String(),
sw.ExternalLabels.String(),
sw.ProxyURL.String(), sw.ProxyAuthConfig.String(), sw.AuthConfig.String(), sw.MetricRelabelConfigs.String(),
sw.SampleLimit, sw.DisableCompression, sw.DisableKeepAlive, sw.StreamParse,
sw.ScrapeAlignInterval, sw.ScrapeOffset, sw.SeriesLimit, sw.NoStaleMarkers)
return key
}
// Job returns job for the ScrapeWork
func (sw *ScrapeWork) Job() string {
return sw.Labels.Get("job")
}
type scrapeWork struct {
// Config for the scrape.
Config *ScrapeWork
// ReadData is called for reading the data.
ReadData func(dst []byte) ([]byte, error)
// GetStreamReader is called if Config.StreamParse is set.
GetStreamReader func() (*streamReader, error)
// PushData is called for pushing collected data.
PushData func(at *auth.Token, wr *prompbmarshal.WriteRequest)
// ScrapeGroup is name of ScrapeGroup that
// scrapeWork belongs to
ScrapeGroup string
tmpRow parser.Row
// This flag is set to true if series_limit is exceeded.
seriesLimitExceeded bool
// labelsHashBuf is used for calculating the hash on series labels
labelsHashBuf []byte
// Optional limiter on the number of unique series per scrape target.
seriesLimiter *bloomfilter.Limiter
// prevBodyLen contains the previous response body length for the given scrape work.
// It is used as a hint in order to reduce memory usage for body buffers.
prevBodyLen int
// prevLabelsLen contains the number labels scraped during the previous scrape.
// It is used as a hint in order to reduce memory usage when parsing scrape responses.
prevLabelsLen int
// lastScrape holds the last response from scrape target.
// It is used for staleness tracking and for populating scrape_series_added metric.
// The lastScrape isn't populated if -promscrape.noStaleMarkers is set. This reduces memory usage.
lastScrape []byte
// lastScrapeCompressed is used for storing the compressed lastScrape between scrapes
// in stream parsing mode in order to reduce memory usage when the lastScrape size
// equals to or exceeds -promscrape.minResponseSizeForStreamParse
lastScrapeCompressed []byte
// nextErrorLogTime is the timestamp in millisecond when the next scrape error should be logged.
nextErrorLogTime int64
// failureRequestsCount is the number of suppressed scrape errors during the last suppressScrapeErrorsDelay
failureRequestsCount int
// successRequestsCount is the number of success requests during the last suppressScrapeErrorsDelay
successRequestsCount int
}
func (sw *scrapeWork) loadLastScrape() string {
if len(sw.lastScrapeCompressed) > 0 {
b, err := encoding.DecompressZSTD(sw.lastScrape[:0], sw.lastScrapeCompressed)
if err != nil {
logger.Panicf("BUG: cannot unpack compressed previous response: %s", err)
}
sw.lastScrape = b
}
return bytesutil.ToUnsafeString(sw.lastScrape)
}
func (sw *scrapeWork) storeLastScrape(lastScrape []byte) {
mustCompress := minResponseSizeForStreamParse.N > 0 && len(lastScrape) >= minResponseSizeForStreamParse.IntN()
if mustCompress {
sw.lastScrapeCompressed = encoding.CompressZSTDLevel(sw.lastScrapeCompressed[:0], lastScrape, 1)
sw.lastScrape = nil
} else {
sw.lastScrape = append(sw.lastScrape[:0], lastScrape...)
sw.lastScrapeCompressed = nil
}
}
func (sw *scrapeWork) finalizeLastScrape() {
if len(sw.lastScrapeCompressed) > 0 {
// The compressed lastScrape is available in sw.lastScrapeCompressed.
// Release the memory occupied by sw.lastScrape, so it won't be occupied between scrapes.
sw.lastScrape = nil
}
if len(sw.lastScrape) > 0 {
// Release the memory occupied by sw.lastScrapeCompressed, so it won't be occupied between scrapes.
sw.lastScrapeCompressed = nil
}
}
func (sw *scrapeWork) run(stopCh <-chan struct{}, globalStopCh <-chan struct{}) {
var randSleep uint64
scrapeInterval := sw.Config.ScrapeInterval
scrapeAlignInterval := sw.Config.ScrapeAlignInterval
scrapeOffset := sw.Config.ScrapeOffset
if scrapeOffset > 0 {
scrapeAlignInterval = scrapeInterval
}
if scrapeAlignInterval <= 0 {
// Calculate start time for the first scrape from ScrapeURL and labels.
// This should spread load when scraping many targets with different
// scrape urls and labels.
// This also makes consistent scrape times across restarts
// for a target with the same ScrapeURL and labels.
//
// Include clusterName to the key in order to guarantee that the same
// scrape target is scraped at different offsets per each cluster.
// This guarantees that the deduplication consistently leaves samples received from the same vmagent.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2679
//
// Include clusterMemberID to the key in order to guarantee that each member in vmagent cluster
// scrapes replicated targets at different time offsets. This guarantees that the deduplication consistently leaves samples
// received from the same vmagent replica.
// See https://docs.victoriametrics.com/vmagent.html#scraping-big-number-of-targets
key := fmt.Sprintf("clusterName=%s, clusterMemberID=%d, ScrapeURL=%s, Labels=%s", *clusterName, clusterMemberID, sw.Config.ScrapeURL, sw.Config.Labels.String())
h := xxhash.Sum64(bytesutil.ToUnsafeBytes(key))
randSleep = uint64(float64(scrapeInterval) * (float64(h) / (1 << 64)))
sleepOffset := uint64(time.Now().UnixNano()) % uint64(scrapeInterval)
if randSleep < sleepOffset {
randSleep += uint64(scrapeInterval)
}
randSleep -= sleepOffset
} else {
d := uint64(scrapeAlignInterval)
randSleep = d - uint64(time.Now().UnixNano())%d
if scrapeOffset > 0 {
randSleep += uint64(scrapeOffset)
}
randSleep %= uint64(scrapeInterval)
}
timer := timerpool.Get(time.Duration(randSleep))
var timestamp int64
var ticker *time.Ticker
select {
case <-stopCh:
timerpool.Put(timer)
return
case <-timer.C:
timerpool.Put(timer)
ticker = time.NewTicker(scrapeInterval)
timestamp = time.Now().UnixNano() / 1e6
sw.scrapeAndLogError(timestamp, timestamp)
}
defer ticker.Stop()
for {
timestamp += scrapeInterval.Milliseconds()
select {
case <-stopCh:
t := time.Now().UnixNano() / 1e6
lastScrape := sw.loadLastScrape()
select {
case <-globalStopCh:
// Do not send staleness markers on graceful shutdown as Prometheus does.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2013#issuecomment-1006994079
default:
// Send staleness markers to all the metrics scraped last time from the target
// when the given target disappears as Prometheus does.
// Use the current real timestamp for staleness markers, so queries
// stop returning data just after the time the target disappears.
sw.sendStaleSeries(lastScrape, "", t, true)
}
if sw.seriesLimiter != nil {
sw.seriesLimiter.MustStop()
sw.seriesLimiter = nil
}
return
case tt := <-ticker.C:
t := tt.UnixNano() / 1e6
if d := math.Abs(float64(t - timestamp)); d > 0 && d/float64(scrapeInterval.Milliseconds()) > 0.1 {
// Too big jitter. Adjust timestamp
timestamp = t
}
sw.scrapeAndLogError(timestamp, t)
}
}
}
func (sw *scrapeWork) logError(s string) {
if !*suppressScrapeErrors {
logger.ErrorfSkipframes(1, "error when scraping %q from job %q with labels %s: %s; "+
"scrape errors can be disabled by -promscrape.suppressScrapeErrors command-line flag",
sw.Config.ScrapeURL, sw.Config.Job(), sw.Config.Labels.String(), s)
}
}
func (sw *scrapeWork) scrapeAndLogError(scrapeTimestamp, realTimestamp int64) {
err := sw.scrapeInternal(scrapeTimestamp, realTimestamp)
if *suppressScrapeErrors {
return
}
if err == nil {
sw.successRequestsCount++
return
}
sw.failureRequestsCount++
if sw.nextErrorLogTime == 0 {
sw.nextErrorLogTime = realTimestamp + suppressScrapeErrorsDelay.Milliseconds()
}
if realTimestamp < sw.nextErrorLogTime {
return
}
totalRequests := sw.failureRequestsCount + sw.successRequestsCount
logger.Warnf("cannot scrape target %q (%s) %d out of %d times during -promscrape.suppressScrapeErrorsDelay=%s; the last error: %s",
sw.Config.ScrapeURL, sw.Config.Labels.String(), sw.failureRequestsCount, totalRequests, *suppressScrapeErrorsDelay, err)
sw.nextErrorLogTime = realTimestamp + suppressScrapeErrorsDelay.Milliseconds()
sw.failureRequestsCount = 0
sw.successRequestsCount = 0
}
var (
scrapeDuration = metrics.NewHistogram("vm_promscrape_scrape_duration_seconds")
scrapeResponseSize = metrics.NewHistogram("vm_promscrape_scrape_response_size_bytes")
scrapedSamples = metrics.NewHistogram("vm_promscrape_scraped_samples")
scrapesSkippedBySampleLimit = metrics.NewCounter("vm_promscrape_scrapes_skipped_by_sample_limit_total")
scrapesFailed = metrics.NewCounter("vm_promscrape_scrapes_failed_total")
pushDataDuration = metrics.NewHistogram("vm_promscrape_push_data_duration_seconds")
)
func (sw *scrapeWork) mustSwitchToStreamParseMode(responseSize int) bool {
if minResponseSizeForStreamParse.N <= 0 {
return false
}
return sw.Config.canSwitchToStreamParseMode() && responseSize >= minResponseSizeForStreamParse.IntN()
}
// getTargetResponse() fetches response from sw target in the same way as when scraping the target.
func (sw *scrapeWork) getTargetResponse() ([]byte, error) {
if *streamParse || sw.Config.StreamParse || sw.mustSwitchToStreamParseMode(sw.prevBodyLen) {
// Read the response in stream mode.
sr, err := sw.GetStreamReader()
if err != nil {
return nil, err
}
data, err := io.ReadAll(sr)
sr.MustClose()
return data, err
}
// Read the response in usual mode.
return sw.ReadData(nil)
}
func (sw *scrapeWork) scrapeInternal(scrapeTimestamp, realTimestamp int64) error {
if *streamParse || sw.Config.StreamParse || sw.mustSwitchToStreamParseMode(sw.prevBodyLen) {
// Read data from scrape targets in streaming manner.
// This case is optimized for targets exposing more than ten thousand of metrics per target.
return sw.scrapeStream(scrapeTimestamp, realTimestamp)
}
// Common case: read all the data from scrape target to memory (body) and then process it.
// This case should work more optimally than stream parse code for common case when scrape target exposes
// up to a few thousand metrics.
body := leveledbytebufferpool.Get(sw.prevBodyLen)
var err error
body.B, err = sw.ReadData(body.B[:0])
releaseBody, err := sw.processScrapedData(scrapeTimestamp, realTimestamp, body, err)
if releaseBody {
leveledbytebufferpool.Put(body)
}
return err
}
var processScrapedDataConcurrencyLimitCh = make(chan struct{}, cgroup.AvailableCPUs())
func (sw *scrapeWork) processScrapedData(scrapeTimestamp, realTimestamp int64, body *bytesutil.ByteBuffer, err error) (bool, error) {
// This function is CPU-bound, while it may allocate big amounts of memory.
// That's why it is a good idea to limit the number of concurrent calls to this function
// in order to limit memory usage under high load without sacrificing the performance.
processScrapedDataConcurrencyLimitCh <- struct{}{}
defer func() {
<-processScrapedDataConcurrencyLimitCh
}()
endTimestamp := time.Now().UnixNano() / 1e6
duration := float64(endTimestamp-realTimestamp) / 1e3
scrapeDuration.Update(duration)
scrapeResponseSize.Update(float64(len(body.B)))
up := 1
wc := writeRequestCtxPool.Get(sw.prevLabelsLen)
lastScrape := sw.loadLastScrape()
bodyString := bytesutil.ToUnsafeString(body.B)
areIdenticalSeries := sw.areIdenticalSeries(lastScrape, bodyString)
if err != nil {
up = 0
scrapesFailed.Inc()
} else {
wc.rows.UnmarshalWithErrLogger(bodyString, sw.logError)
}
srcRows := wc.rows.Rows
samplesScraped := len(srcRows)
scrapedSamples.Update(float64(samplesScraped))
for i := range srcRows {
sw.addRowToTimeseries(wc, &srcRows[i], scrapeTimestamp, true)
}
samplesPostRelabeling := len(wc.writeRequest.Timeseries)
if sw.Config.SampleLimit > 0 && samplesPostRelabeling > sw.Config.SampleLimit {
wc.resetNoRows()
up = 0
scrapesSkippedBySampleLimit.Inc()
err = fmt.Errorf("the response from %q exceeds sample_limit=%d; "+
"either reduce the sample count for the target or increase sample_limit", sw.Config.ScrapeURL, sw.Config.SampleLimit)
}
if up == 0 {
bodyString = ""
}
seriesAdded := 0
if !areIdenticalSeries {
// The returned value for seriesAdded may be bigger than the real number of added series
// if some series were removed during relabeling.
// This is a trade-off between performance and accuracy.
seriesAdded = sw.getSeriesAdded(lastScrape, bodyString)
}
samplesDropped := 0
if sw.seriesLimitExceeded || !areIdenticalSeries {
samplesDropped = sw.applySeriesLimit(wc)
}
am := &autoMetrics{
up: up,
scrapeDurationSeconds: duration,
samplesScraped: samplesScraped,
samplesPostRelabeling: samplesPostRelabeling,
seriesAdded: seriesAdded,
seriesLimitSamplesDropped: samplesDropped,
}
sw.addAutoMetrics(am, wc, scrapeTimestamp)
sw.pushData(sw.Config.AuthToken, &wc.writeRequest)
sw.prevLabelsLen = len(wc.labels)
sw.prevBodyLen = len(bodyString)
wc.reset()
mustSwitchToStreamParse := sw.mustSwitchToStreamParseMode(len(bodyString))
if !mustSwitchToStreamParse {
// Return wc to the pool if the parsed response size was smaller than -promscrape.minResponseSizeForStreamParse
// This should reduce memory usage when scraping targets with big responses.
writeRequestCtxPool.Put(wc)
}
// body must be released only after wc is released, since wc refers to body.
if !areIdenticalSeries {
// Send stale markers for disappeared metrics with the real scrape timestamp
// in order to guarantee that query doesn't return data after this time for the disappeared metrics.
sw.sendStaleSeries(lastScrape, bodyString, realTimestamp, false)
sw.storeLastScrape(body.B)
}
sw.finalizeLastScrape()
tsmGlobal.Update(sw, up == 1, realTimestamp, int64(duration*1000), samplesScraped, err)
return !mustSwitchToStreamParse, err
}
func (sw *scrapeWork) pushData(at *auth.Token, wr *prompbmarshal.WriteRequest) {
startTime := time.Now()
sw.PushData(at, wr)
pushDataDuration.UpdateDuration(startTime)
}
type streamBodyReader struct {
body []byte
bodyLen int
readOffset int
}
func (sbr *streamBodyReader) Init(sr *streamReader) error {
sbr.body = nil
sbr.bodyLen = 0
sbr.readOffset = 0
// Read the whole response body in memory before parsing it in stream mode.
// This minimizes the time needed for reading response body from scrape target.
startTime := fasttime.UnixTimestamp()
body, err := io.ReadAll(sr)
if err != nil {
d := fasttime.UnixTimestamp() - startTime
return fmt.Errorf("cannot read stream body in %d seconds: %w", d, err)
}
sbr.body = body
sbr.bodyLen = len(body)
return nil
}
func (sbr *streamBodyReader) Read(b []byte) (int, error) {
if sbr.readOffset >= len(sbr.body) {
return 0, io.EOF
}
n := copy(b, sbr.body[sbr.readOffset:])
sbr.readOffset += n
return n, nil
}
func (sw *scrapeWork) scrapeStream(scrapeTimestamp, realTimestamp int64) error {
samplesScraped := 0
samplesPostRelabeling := 0
wc := writeRequestCtxPool.Get(sw.prevLabelsLen)
// Do not pool sbr and do not pre-allocate sbr.body in order to reduce memory usage when scraping big responses.
var sbr streamBodyReader
lastScrape := sw.loadLastScrape()
bodyString := ""
areIdenticalSeries := true
samplesDropped := 0
sr, err := sw.GetStreamReader()
if err != nil {
err = fmt.Errorf("cannot read data: %s", err)
} else {
var mu sync.Mutex
err = sbr.Init(sr)
if err == nil {
bodyString = bytesutil.ToUnsafeString(sbr.body)
areIdenticalSeries = sw.areIdenticalSeries(lastScrape, bodyString)
err = stream.Parse(&sbr, scrapeTimestamp, false, func(rows []parser.Row) error {
mu.Lock()
defer mu.Unlock()
samplesScraped += len(rows)
for i := range rows {
sw.addRowToTimeseries(wc, &rows[i], scrapeTimestamp, true)
}
samplesPostRelabeling += len(wc.writeRequest.Timeseries)
if sw.Config.SampleLimit > 0 && samplesPostRelabeling > sw.Config.SampleLimit {
wc.resetNoRows()
scrapesSkippedBySampleLimit.Inc()
return fmt.Errorf("the response from %q exceeds sample_limit=%d; "+
"either reduce the sample count for the target or increase sample_limit", sw.Config.ScrapeURL, sw.Config.SampleLimit)
}
if sw.seriesLimitExceeded || !areIdenticalSeries {
samplesDropped += sw.applySeriesLimit(wc)
}
// Push the collected rows to sw before returning from the callback, since they cannot be held
// after returning from the callback - this will result in data race.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/825#issuecomment-723198247
sw.pushData(sw.Config.AuthToken, &wc.writeRequest)
wc.resetNoRows()
return nil
}, sw.logError)
}
sr.MustClose()
}
scrapedSamples.Update(float64(samplesScraped))
endTimestamp := time.Now().UnixNano() / 1e6
duration := float64(endTimestamp-realTimestamp) / 1e3
scrapeDuration.Update(duration)
scrapeResponseSize.Update(float64(sbr.bodyLen))
up := 1
if err != nil {
// Mark the scrape as failed even if it already read and pushed some samples
// to remote storage. This makes the logic compatible with Prometheus.
up = 0
scrapesFailed.Inc()
}
seriesAdded := 0
if !areIdenticalSeries {
// The returned value for seriesAdded may be bigger than the real number of added series
// if some series were removed during relabeling.
// This is a trade-off between performance and accuracy.
seriesAdded = sw.getSeriesAdded(lastScrape, bodyString)
}
am := &autoMetrics{
up: up,
scrapeDurationSeconds: duration,
samplesScraped: samplesScraped,
samplesPostRelabeling: samplesPostRelabeling,
seriesAdded: seriesAdded,
seriesLimitSamplesDropped: samplesDropped,
}
sw.addAutoMetrics(am, wc, scrapeTimestamp)
sw.pushData(sw.Config.AuthToken, &wc.writeRequest)
sw.prevLabelsLen = len(wc.labels)
sw.prevBodyLen = sbr.bodyLen
wc.reset()
writeRequestCtxPool.Put(wc)
if !areIdenticalSeries {
// Send stale markers for disappeared metrics with the real scrape timestamp
// in order to guarantee that query doesn't return data after this time for the disappeared metrics.
sw.sendStaleSeries(lastScrape, bodyString, realTimestamp, false)
sw.storeLastScrape(sbr.body)
}
sw.finalizeLastScrape()
tsmGlobal.Update(sw, up == 1, realTimestamp, int64(duration*1000), samplesScraped, err)
// Do not track active series in streaming mode, since this may need too big amounts of memory
// when the target exports too big number of metrics.
return err
}
func (sw *scrapeWork) areIdenticalSeries(prevData, currData string) bool {
if sw.Config.NoStaleMarkers && sw.Config.SeriesLimit <= 0 {
// Do not spend CPU time on tracking the changes in series if stale markers are disabled.
// The check for series_limit is needed for https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3660
return true
}
return parser.AreIdenticalSeriesFast(prevData, currData)
}
// leveledWriteRequestCtxPool allows reducing memory usage when writeRequesCtx
// structs contain mixed number of labels.
//
// Its logic has been copied from leveledbytebufferpool.
type leveledWriteRequestCtxPool struct {
pools [13]sync.Pool
}
func (lwp *leveledWriteRequestCtxPool) Get(labelsCapacity int) *writeRequestCtx {
id, capacityNeeded := lwp.getPoolIDAndCapacity(labelsCapacity)
for i := 0; i < 2; i++ {
if id < 0 || id >= len(lwp.pools) {
break
}
if v := lwp.pools[id].Get(); v != nil {
return v.(*writeRequestCtx)
}
id++
}
return &writeRequestCtx{
labels: make([]prompbmarshal.Label, 0, capacityNeeded),
}
}
func (lwp *leveledWriteRequestCtxPool) Put(wc *writeRequestCtx) {
capacity := cap(wc.labels)
id, poolCapacity := lwp.getPoolIDAndCapacity(capacity)
if capacity <= poolCapacity {
wc.reset()
lwp.pools[id].Put(wc)
}
}
func (lwp *leveledWriteRequestCtxPool) getPoolIDAndCapacity(size int) (int, int) {
size--
if size < 0 {
size = 0
}
size >>= 3
id := bits.Len(uint(size))
if id >= len(lwp.pools) {
id = len(lwp.pools) - 1
}
return id, (1 << (id + 3))
}
type writeRequestCtx struct {
rows parser.Rows
writeRequest prompbmarshal.WriteRequest
labels []prompbmarshal.Label
samples []prompbmarshal.Sample
}
func (wc *writeRequestCtx) reset() {
wc.rows.Reset()
wc.resetNoRows()
}
func (wc *writeRequestCtx) resetNoRows() {
prompbmarshal.ResetWriteRequest(&wc.writeRequest)
labels := wc.labels
for i := range labels {
label := &labels[i]
label.Name = ""
label.Value = ""
}
wc.labels = wc.labels[:0]
wc.samples = wc.samples[:0]
}
var writeRequestCtxPool leveledWriteRequestCtxPool
func (sw *scrapeWork) getSeriesAdded(lastScrape, currScrape string) int {
if currScrape == "" {
return 0
}
bodyString := parser.GetRowsDiff(currScrape, lastScrape)
return strings.Count(bodyString, "\n")
}
func (sw *scrapeWork) applySeriesLimit(wc *writeRequestCtx) int {
if sw.Config.SeriesLimit <= 0 {
return 0
}
if sw.seriesLimiter == nil {
sw.seriesLimiter = bloomfilter.NewLimiter(sw.Config.SeriesLimit, 24*time.Hour)
}
sl := sw.seriesLimiter
dstSeries := wc.writeRequest.Timeseries[:0]
samplesDropped := 0
for _, ts := range wc.writeRequest.Timeseries {
h := sw.getLabelsHash(ts.Labels)
if !sl.Add(h) {
samplesDropped++
continue
}
dstSeries = append(dstSeries, ts)
}
prompbmarshal.ResetTimeSeries(wc.writeRequest.Timeseries[len(dstSeries):])
wc.writeRequest.Timeseries = dstSeries
if samplesDropped > 0 && !sw.seriesLimitExceeded {
sw.seriesLimitExceeded = true
}
return samplesDropped
}
var sendStaleSeriesConcurrencyLimitCh = make(chan struct{}, cgroup.AvailableCPUs())
func (sw *scrapeWork) sendStaleSeries(lastScrape, currScrape string, timestamp int64, addAutoSeries bool) {
// This function is CPU-bound, while it may allocate big amounts of memory.
// That's why it is a good idea to limit the number of concurrent calls to this function
// in order to limit memory usage under high load without sacrificing the performance.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3668
sendStaleSeriesConcurrencyLimitCh <- struct{}{}
defer func() {
<-sendStaleSeriesConcurrencyLimitCh
}()
if sw.Config.NoStaleMarkers {
return
}
bodyString := lastScrape
if currScrape != "" {
bodyString = parser.GetRowsDiff(lastScrape, currScrape)
}
wc := writeRequestCtxPool.Get(sw.prevLabelsLen)
defer func() {
wc.reset()
writeRequestCtxPool.Put(wc)
}()
if bodyString != "" {
// Send stale markers in streaming mode in order to reduce memory usage
// when stale markers for targets exposing big number of metrics must be generated.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3668
// and https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3675
var mu sync.Mutex
br := bytes.NewBufferString(bodyString)
err := stream.Parse(br, timestamp, false, func(rows []parser.Row) error {
mu.Lock()
defer mu.Unlock()
for i := range rows {
sw.addRowToTimeseries(wc, &rows[i], timestamp, true)
}
// Apply series limit to stale markers in order to prevent sending stale markers for newly created series.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3660
if sw.seriesLimitExceeded {
sw.applySeriesLimit(wc)
}
// Push the collected rows to sw before returning from the callback, since they cannot be held
// after returning from the callback - this will result in data race.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/825#issuecomment-723198247
setStaleMarkersForRows(wc.writeRequest.Timeseries)
sw.pushData(sw.Config.AuthToken, &wc.writeRequest)
wc.resetNoRows()
return nil
}, sw.logError)
if err != nil {
sw.logError(fmt.Errorf("cannot send stale markers: %s", err).Error())
}
}
if addAutoSeries {
am := &autoMetrics{}
sw.addAutoMetrics(am, wc, timestamp)
}
setStaleMarkersForRows(wc.writeRequest.Timeseries)
sw.pushData(sw.Config.AuthToken, &wc.writeRequest)
}
func setStaleMarkersForRows(series []prompbmarshal.TimeSeries) {
for _, tss := range series {
samples := tss.Samples
for i := range samples {
samples[i].Value = decimal.StaleNaN
}
staleSamplesCreated.Add(len(samples))
}
}
var staleSamplesCreated = metrics.NewCounter(`vm_promscrape_stale_samples_created_total`)
func (sw *scrapeWork) getLabelsHash(labels []prompbmarshal.Label) uint64 {
// It is OK if there will be hash collisions for distinct sets of labels,
// since the accuracy for `scrape_series_added` metric may be lower than 100%.
b := sw.labelsHashBuf[:0]
for _, label := range labels {
b = append(b, label.Name...)
b = append(b, label.Value...)
}
sw.labelsHashBuf = b
return xxhash.Sum64(b)
}
type autoMetrics struct {
up int
scrapeDurationSeconds float64
samplesScraped int
samplesPostRelabeling int
seriesAdded int
seriesLimitSamplesDropped int
}
func isAutoMetric(s string) bool {
switch s {
case "up", "scrape_duration_seconds", "scrape_samples_scraped",
"scrape_samples_post_metric_relabeling", "scrape_series_added",
"scrape_timeout_seconds", "scrape_samples_limit",
"scrape_series_limit_samples_dropped", "scrape_series_limit",
"scrape_series_current":
return true
}
return false
}
func (sw *scrapeWork) addAutoMetrics(am *autoMetrics, wc *writeRequestCtx, timestamp int64) {
sw.addAutoTimeseries(wc, "up", float64(am.up), timestamp)
sw.addAutoTimeseries(wc, "scrape_duration_seconds", am.scrapeDurationSeconds, timestamp)
sw.addAutoTimeseries(wc, "scrape_samples_scraped", float64(am.samplesScraped), timestamp)
sw.addAutoTimeseries(wc, "scrape_samples_post_metric_relabeling", float64(am.samplesPostRelabeling), timestamp)
sw.addAutoTimeseries(wc, "scrape_series_added", float64(am.seriesAdded), timestamp)
sw.addAutoTimeseries(wc, "scrape_timeout_seconds", sw.Config.ScrapeTimeout.Seconds(), timestamp)
if sampleLimit := sw.Config.SampleLimit; sampleLimit > 0 {
// Expose scrape_samples_limit metric if sample_limt config is set for the target.
// See https://github.com/VictoriaMetrics/operator/issues/497
sw.addAutoTimeseries(wc, "scrape_samples_limit", float64(sampleLimit), timestamp)
}
if sl := sw.seriesLimiter; sl != nil {
sw.addAutoTimeseries(wc, "scrape_series_limit_samples_dropped", float64(am.seriesLimitSamplesDropped), timestamp)
sw.addAutoTimeseries(wc, "scrape_series_limit", float64(sl.MaxItems()), timestamp)
sw.addAutoTimeseries(wc, "scrape_series_current", float64(sl.CurrentItems()), timestamp)
}
}
// addAutoTimeseries adds automatically generated time series with the given name, value and timestamp.
//
// See https://prometheus.io/docs/concepts/jobs_instances/#automatically-generated-labels-and-time-series
func (sw *scrapeWork) addAutoTimeseries(wc *writeRequestCtx, name string, value float64, timestamp int64) {
sw.tmpRow.Metric = name
sw.tmpRow.Tags = nil
sw.tmpRow.Value = value
sw.tmpRow.Timestamp = timestamp
sw.addRowToTimeseries(wc, &sw.tmpRow, timestamp, false)
}
func (sw *scrapeWork) addRowToTimeseries(wc *writeRequestCtx, r *parser.Row, timestamp int64, needRelabel bool) {
metric := r.Metric
// Add `exported_` prefix to metrics, which clash with the automatically generated
// metric names only if the following conditions are met:
//
// - The `honor_labels` option isn't set to true in the scrape_config.
// If `honor_labels: true`, then the scraped metric name must remain unchanged
// because the user explicitly asked about it in the config.
// - The metric has no labels (tags). If it has labels, then the metric value
// will be written into a separate time series comparing to automatically generated time series.
//
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3557
// and https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3406
if needRelabel && !sw.Config.HonorLabels && len(r.Tags) == 0 && isAutoMetric(metric) {
bb := bbPool.Get()
bb.B = append(bb.B, "exported_"...)
bb.B = append(bb.B, metric...)
metric = bytesutil.InternBytes(bb.B)
bbPool.Put(bb)
}
labelsLen := len(wc.labels)
targetLabels := sw.Config.Labels.GetLabels()
wc.labels = appendLabels(wc.labels, metric, r.Tags, targetLabels, sw.Config.HonorLabels)
if needRelabel {
wc.labels = sw.Config.MetricRelabelConfigs.Apply(wc.labels, labelsLen)
}
wc.labels = promrelabel.FinalizeLabels(wc.labels[:labelsLen], wc.labels[labelsLen:])
if len(wc.labels) == labelsLen {
// Skip row without labels.
return
}
// Add labels from `global->external_labels` section after the relabeling like Prometheus does.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3137
externalLabels := sw.Config.ExternalLabels.GetLabels()
wc.labels = appendExtraLabels(wc.labels, externalLabels, labelsLen, sw.Config.HonorLabels)
sampleTimestamp := r.Timestamp
if !sw.Config.HonorTimestamps || sampleTimestamp == 0 {
sampleTimestamp = timestamp
}
wc.samples = append(wc.samples, prompbmarshal.Sample{
Value: r.Value,
Timestamp: sampleTimestamp,
})
wr := &wc.writeRequest
wr.Timeseries = append(wr.Timeseries, prompbmarshal.TimeSeries{
Labels: wc.labels[labelsLen:],
Samples: wc.samples[len(wc.samples)-1:],
})
}
var bbPool bytesutil.ByteBufferPool
func appendLabels(dst []prompbmarshal.Label, metric string, src []parser.Tag, extraLabels []prompbmarshal.Label, honorLabels bool) []prompbmarshal.Label {
dstLen := len(dst)
dst = append(dst, prompbmarshal.Label{
Name: "__name__",
Value: metric,
})
for i := range src {
tag := &src[i]
dst = append(dst, prompbmarshal.Label{
Name: tag.Key,
Value: tag.Value,
})
}
return appendExtraLabels(dst, extraLabels, dstLen, honorLabels)
}
func appendExtraLabels(dst, extraLabels []prompbmarshal.Label, offset int, honorLabels bool) []prompbmarshal.Label {
// Add extraLabels to labels.
// Handle duplicates in the same way as Prometheus does.
if len(dst) == offset {
// Fast path - add extraLabels to dst without the need to de-duplicate.
dst = append(dst, extraLabels...)
return dst
}
offsetEnd := len(dst)
for _, label := range extraLabels {
labels := dst[offset:offsetEnd]
prevLabel := promrelabel.GetLabelByName(labels, label.Name)
if prevLabel == nil {
// Fast path - the label doesn't exist in labels, so just add it to dst.
dst = append(dst, label)
continue
}
if honorLabels {
// Skip the extra label with the same name.
continue
}
// Rename the prevLabel to "exported_" + label.Name
// See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#scrape_config
exportedName := "exported_" + label.Name
exportedLabel := promrelabel.GetLabelByName(labels, exportedName)
if exportedLabel != nil {